WASHINGTON -- A federal grand jury formally charged Osama bin Laden yesterday in the bombings of two U.S. embassies in Africa, describing the Saudi exile as the leader of a nine-year conspiracy, reaching from the Philippines to New York, to kill Americans.

The indictment, returned in U.S. District Court in Manhattan, marked the first time that bin Laden himself has been charged in the bombings, though U.S. officials had blamed him within hours of the two blasts Aug. 7. Those bombings killed 213 people -- including 12 Americans -- in Nairobi, Kenya, and 11 people in Dar es Salaam, Tanzania. Thousands more were injured.

Muhammad Atef, a man identified as military commander of bin Laden's organization, was also accused in the 50-page indictment. The State Department announced rewards of up to $5 million each for the arrest and conviction of bin Laden and Atef. Bin Laden, heir to a Saudi construction fortune, was last reported to be in Afghanistan.

Four other men were also charged in the conspiracy.

"This is an important step forward in our fight against terrorism," Attorney General Janet Reno said in a statement. "It sends a message that no terrorist can flout our laws and murder innocent civilians."

"The purpose of this now is to generate some information to arrest [Bin Laden]," Lewis Schiliro, head of the FBI's New York office, told reporters there, according to Reuters. "Obviously, the attempts we made covertly did not work. Hopefully, by going overt, by unsealing the indictment, it will give us a different perspective."

The United States has already retaliated against bin Laden, by firing cruise missiles into training camps in Afghanistan and into a pharmaceutical plant in Khartoum, the Sudanese capital. U.S. officials have claimed that this plant was involved in the production or storage of components for nerve gas, but the proof that has been made public is sketchy.

The indictment charges that bin Laden led an umbrella of organizations operating in 20 countries. These organizations, the indictment asserts, included a group headed by the blind Egyptian Cleric Omar Abdel-Rahman, who was convicted of plotting to blow up New York City landmarks.

Among other crimes, the conspirators aimed to kill American military personnel in Somalia and Saudi Arabia, according to the indictment. The conspiracy also included efforts to obtain components of nuclear and chemical weapons, the indictment charges.

Bin Laden and his organization, al Qaeda, forged alliances with the ruling National Islamic Front in Sudan as well as with representatives of the Iranian government and the Iran-backed Hezbollah guerrilla organization in Lebanon.

Al Qaeda, or "the Base," opposed U.S. military involvement in the 1991 Persian Gulf war and the intervention in Somalia late in 1992 because it saw these actions as pretexts to prepare the way for an American occupation of Islamic countries, according to the indictment.

A federal investigation into bin Laden's leadership role in international terrorism began in 1996, long before the August attacks. Bin Laden himself was secretly charged by a U.S. grand jury in June, reportedly with conspiring to kill Americans. But the indictment returned yesterday was the first to link him directly to the embassy bombings Aug. 7.

Announcing the indictment in New York, U.S. Attorney Mary Jo White said that beginning in 1992, bin Laden issued a series of escalating fatwahs, or religious opinions, urging followers to kill Americans.

These included a February fatwah saying that Muslims should kill Americans anywhere in the world, and a televised threat in May in which bin Laden said he did not distinguish between military and civilian personnel.

The new charges indicate that American authorities have made surprisingly swift progress in amassing evidence since launching the largest overseas inquiry ever undertaken by the FBI.

A senior law enforcement official had said last month that it could be years before enough concrete evidence was collected to tie bin Laden directly to the bombings.

Besides the August bombings, the indictment charges that the conspiracy involved establishing front companies, providing false identities and travel documents and providing false information to authorities in various countries.

One link between the actual embassy bombers and bin Laden, according to the indictment, occurred in 1996, when one of the men previously charged in the case, Mohamed Rashed Daoud al-'Owhali, received terrorist training in camps in Afghanistan and then met with bin Laden to ask him for a "mission."

Two years later, he joined confederates in Nairobi, the Kenyan capital, who were in the final stages of planning the Aug. 7 attack on the U.S. embassy. According to the indictment, Daoud al-'Owhali and the man who actually detonated Nairobi bomb -- identified only as Azzam -- both expected to be killed as martyrs in the bombings.

Years before the bombings in Kenya and Tanzania, members of bin Laden's umbrella terrorist organization set out to kill American soldiers who were part of the U.S. operation Restore Hope in Somalia, according to the indictment. That operation began as a mission to relieve widespread starvation in the Horn of Africa nation but turned into a crackdown on militias loyal to warlord Mohamed Farah Aidid.

According to the indictment, Atef traveled to Somalia on several occasions to assess how to attack American and United Nations forces there and offered training to Somalian tribes opposed to the U.N. intervention there. Members of those tribes participated in the October 1993 attack that killed 18 American soldiers.

Members of al Qaeda were also involved in the shipment of weapons from Sudan to Saudi Arabia, according to the indictment.